Surge protectors protect voltage sensitive equipment connected to electrical lines by discharging high voltage signals or current surges to ground before the high voltage signal can damage the equipment. Telecommunications systems employ very large numbers of surge protectors to connect voltage sensitive switching equipment and other equipment to outside phone lines. Phone lines, which normally carry relatively low voltage message signals, are subject to current surges caused by lightning and other extrinsic phenomena associated with the location of the phone lines.
Each phone line includes a pair of wires, referred to as the "tip" line and the "ring" line, that carry the message signal. Each tip and ring line is connected through an industry standard surge protector module having five pins: one for an incoming wire and one for an outgoing wire for each tip line; one for an incoming wire and one outgoing wire for each ring line; and one to connect to ground. The surge protector module passes low-voltage signals traveling between the incoming and outgoing wires for a given line, but discharges current surges on the line to the ground pin, which in turn is connected to ground.
Because of the large number of phone lines, connecting surge protectors to each of the lines is a labor intensive task. The conventional method for connecting the cables to the protector block has been to manually wire-wrap each line to the proper pin on the protector block. Wire wrapping involves cutting each conductor to a proper length, stripping the insulation off of each conductor and wrapping each conductor around the proper pin. Because phone lines are bundled together in cables, surge protectors are also bundled using a "protector block." A protector block in essence serves a function of providing a rigid structural platform for supporting a plurality of surge protector modules for coupling to multi-line telecommunications cables. Generally, protector blocks come in sizes that handle ten, twenty-five, fifty and one hundred surge protectors for coupling to an equal number of communication lines.
A protector block is fabricated as a single slab of plastic insulating material. On one side is a plurality of wire-wrap pins, one for each wire. On the opposite side, there is, for each wire-wrap pin, a female socket electrically connected to one wire wrap pin. The pins and the sockets are arranged in groups of five, with the pins in each group having predetermined configuration depending on the type of surge protector module being used. Each surge protector module has five pins that are inserted into the appropriate socket to establish a compression fit electrical connection with the socket and the wire-wrap pin.
After wire wrapping, cables are then anchored to an aluminum hood or shroud that extends over the pins of the protector block. The free-end of each cables is usually already fitted with a connector so that the entire assembly may be easily connected into a telecommunications system.
Wiring a protector block requires a significant amount of time and labor that limits production rates and generally increases the cost of assembly. As with any repetitive, manual process, quality control is a problem. Wiring mistakes occur and they must be found and then corrected, requiring more time and money. Sometimes a cable is bad or needs to be replaced because a different type of connector is needed to connect the cable to the system. A significant amount of time is required to unwrap the cable and rewrap a new cable.